When calculating a decay width of a charmonium state, we adopt the numerical
wave function for a charmonium state calculated by the LP and SP models from our previous work [1]}.
For the emitted charmed mesons in a decay process, such as \(D\)  and \(D^*\) , we use
simple harmonic oscillator (SHO) wave functions as an approximation,
\(\begin{aligned}\Psi _{n L M_L} (\mathbf {P})& = \frac{(-1)^n (-i)^L}{\beta ^{(3/2)}} \sqrt{\frac{2 n!}{\Gamma (n+L+3/2)}} \left(\frac{P}{\beta }\right)^L \\& \times e^{-\frac{P^2}{2 \beta ^2}} L_n^{L+1/2} \left(\frac{P^2}{\beta ^2}\right) Y_{L M_L} (\Omega _P),\end{aligned}\) 
